The other day i found a pair of 3D red/blue glasses in a pile of stuff in my room. I remembered seeing a 3D option in Minecraft, so I tried it out. It was glorious! Beautiful landscapes stretched into my monitor. Cave systems became easier to navigate. I looked down from dizzying heights and saw holes in the ground leading to caves I hadn't noticed. The only downside was that some colors were a little off, making it difficult to tell different blocks in my inventory apart.
Does anyone else play on 3D mode? Why doesn't anyone ever post 3D screenshots?
If you haven't tried it, go to http://www.rainbowsymphony.com/freestuff.html and send away for a free pair of 3D red/blue anaglyph glasses.

I found a workaround. You need a world with part of the nether explored, or a world from a multiplayer server with hellworld=true. Open the world folder. Go into the DIM-1 folder and copy one or more folders from here. Open the world folder of the world you want to insert Nether into. Paste the folders directly in the World folder, overwriting the corresponding chunks. Now you should have Nether chunks in your normal world.

You could do something similar to stick some normal world chunks into the Nether.

I can't get this to work. When I change the setting and restart the game my old world is rewritten by a completely new world, rather than loading new chunks at the edges of my original world. Did Notch change something? Can anyone confirm that this is still working for them?

However, when I started making a portal compass--mapping out the Overworld with the Netherworld, I was able to build portals that properly corresponded to one another. I eventually got a portal in my base and have been steadily building portal chains with that initial portal as my Center point. All portals are taken in relation to it--for the time being.

Can you elaborate? How did you map the Overworld with the Netherworld? What do you mean by "portal compass"? Hod did you build portal chains?

This thread shows the best water elevator I've seen. It describes how to construct a 5x2 water elevator (two 2x2 shafts with a 2x1 separation), with a boat that cycles up and down. viewtopic.php?f=35&t=18733#p339187